beginner concepts

PIC, AVR, and Arduino are ubiquitous in projects these days and a lot of the time it’s easy to over-complicate things with their use. In this case, [Tod] wanted to use a momentary tactile switch to turn something on and off. Instead of going with a microcontroller he built the circuit around a 555 timer. What he really needed in this case is a flip-flop but lacking a chip for that he went with the 555 because it has one built-in. Three resistors and a capacitor later he’s in business, adding another resistor and a transistor to deal with the load switching. We’ve embedded video of the circuit controlling an LED after the break. This IC ends up in a lot of projects so dig through your parts bin and give this circuit a try.

A rudimentary understanding of digital logic and simple integrated circuits is critical if you’re ever going to pull off some really gnarly hacks. [Daniel] put together an explanation about the use of 4511 BCD 7-segment drivers. These chips take binary data in and output decimal data to a 7-segment LED display. In short, they can read 0b1001 from input pins and light the numeral ‘9’ on the display. The best part is that you can build this example circuit in the Atanua logic simulator without ordering parts. We love zero-cost learning!